Update clang-format to version 11

This is taken from the Godot repository, so formatting is similar. This
updates the style rules as well.

Also fix style in files to conform with this version.

include/core/CameraMatrix.hpp

@@ -14,7 +14,6 @@ using namespace godot;
 } // namespace
 
 struct CameraMatrix {
-
 	enum Planes {
 		PLANE_NEAR,
 		PLANE_FAR,
@@ -84,7 +83,6 @@ struct CameraMatrix {
 };
 
 Vector3 CameraMatrix::xform(const Vector3 &p_vec3) const {
-
 	Vector3 ret;
 	ret.x = matrix[0][0] * p_vec3.x + matrix[1][0] * p_vec3.y + matrix[2][0] * p_vec3.z + matrix[3][0];
 	ret.y = matrix[0][1] * p_vec3.x + matrix[1][1] * p_vec3.y + matrix[2][1] * p_vec3.z + matrix[3][1];